Compositions containing alpha -sulfofatty acid esters and methods of making and using the same

Abstract

The invention includes compositions containing one or more alpha -sulfofatty acid esters, and methods for making and using the same. At least one alpha -sulfofatty acid ester is included in an inner portion. The invented composition can further include an outer portion which protects the alpha -sulfofatty acid ester from di-salt formation. The resulting composition improves the stability of the alpha -sulfofatty acid ester after manufacture, during shipping and storage, and in detergents. The invention further included detergents containing the invented composition, and methods of making such detergents.

Description

The present invention generally relates to detergent compositions and additives used in those compositions. Specifically, the present invention relates to compositions containing .alpha.-sulfofatty acid esters that can be additives to a detergent, and methods for making and using the same.Detergent compositions have been known and used as cleaning agents for many years. See U.S. Pat. Nos. 5,783,540, 5,133,892, 4,219,435, 5,358,655, 4,913,832, 5,324,649, 5,397,494, 4,828,745, 4,588,080, 4,518,516, 5,482,641, 4,569,780, 4,828,749, Re. 32,763, and Re. 32,818, the disclosures of which are incorporated herein by reference. A large number of surfactants have been used with detergents because of their excellent surface-activity characteristics. Recently, interest in .alpha.-sulfofatty acid esters (also referred to hereafter as "sulfofatty acids") has increased due to the superior cleaning properties of these compounds. For example, see U.S. Pat. Nos. 5,681,803, 4,816,188, 5,688,982, 5,475,...

AI Technical Summary

Benefits of technology

It is an object of the present invention to provide a composition that protects .alpha.-sulfofatty acid esters from di-salt formation.

The present invention includes compositions having an inner portion containing .alpha.-sulfofatty acid ester and an outer portion on any part of the inner portion. Preferably, the outer portion is disposed on any outer surface of the inner portion. More preferably, the outer portion is a coating. The outer portion inhibits di-salt formation by protecting the sulfofatty acid from base-catalyzed di-salt formation, and from substances or conditions, such as moisture alone or in combination with an elevated temperature, which accelerate or increase di-salt formation. Such protection can occur by physically or chemically blocking the sulfofatty acid from exposure to substances of conditions which cause di-salt formation, or by neutralizing di-salt forming substances before they interact with sulfofatty acid. By providing such protection, the invented sulfofatty acid composition beneficially extends the useful life of .alpha.-sulfofatty acid ester after its manufacture, during shipping and storage, and / or as a detergent ingredient.

Suitable inert ingredients will include salts, such as sodium chloride and sodium sulfate. These salts can be combined with one or more sulfofatty acids to provide a less concentrated inner portion containing at least one .alpha.-sulfofatty acid ester. Similarly, the inert ingredients can be combined with C.sub.12 and / or C.sub.14 .alpha.-sulfofatty acid ester to provide a better substrate for receiving the outer portion. In particular, combining C.sub.12 and / or C.sub.14 .alpha.-sulfofatty acid ester with inert ingredients, such as about 1 to about 35 weight percent sodium chloride or sodium sulfate, can provide a firmer substrate for receiving the outer portion.

Problems solved by technology

The mono-salts are unstable, however, and react with alkali-containing detergent components to form di-salts.

To compensate, more mono-salt of the sulfofatty acid must be added to a detergent mixture to provide the same level of surface active agent performance, which increases the cost and unit size of the detergent.